Specific problems related to the general phenomena of cell growth and development are being examined by use of the combined methodologies of cell biology, biochemistry and genetics. The general approach is to use defined populations of both prokaryotic and eukaryotic cells to investigate 1) the synthesis and function of gene products specifically associated with cell growth and development; 2) interactions of cells with their environment leading to alterations in cell structure and function; 3) interactions of cells with each other leading to altered patterns of growth and differentiation; and 4) the role of metabolites and small regulatory molecules in cell differentiation. Specific research projects include 1) regulation of growth and programmed patterns of development in the bacterium Caulobacter crescentus and in Volvox; 2) metabolism and function of cyclic GMP during the cell cycle of B. emersonii and the role of multifunctional bacterial proteins in the replication of viral RNA; 3) control of cell differentiation in hydra and in Dictyostelium; 4) genetic approaches to the in vivo functions of E. coli exonuclease VII; and 5) developmental and genetic analyses of motility in Dictyostelium.